root/crypto/sha1_generic.c

DEFINITIONS

1. sha1_init
2. sha1_update
3. sha1_final
4. sha1_generic_mod_init
5. sha1_generic_mod_fini

/*
 * Cryptographic API.
 *
 * SHA1 Secure Hash Algorithm.
 *
 * Derived from cryptoapi implementation, adapted for in-place
 * scatterlist interface.
 *
 * Copyright (c) Alan Smithee.
 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
 * Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/crypto.h>
#include <linux/cryptohash.h>
#include <linux/types.h>
#include <crypto/sha.h>
#include <asm/byteorder.h>

struct sha1_ctx {
        u64 count;
        u32 state[5];
        u8 buffer[64];
};

static void sha1_init(struct crypto_tfm *tfm)
{
        struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
        static const struct sha1_ctx initstate = {
          0,
          { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
          { 0, }
        };

        *sctx = initstate;
}

static void sha1_update(struct crypto_tfm *tfm, const u8 *data,
                        unsigned int len)
{
        struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
        unsigned int partial, done;
        const u8 *src;

        partial = sctx->count & 0x3f;
        sctx->count += len;
        done = 0;
        src = data;

        if ((partial + len) > 63) {
                u32 temp[SHA_WORKSPACE_WORDS];

                if (partial) {
                        done = -partial;
                        memcpy(sctx->buffer + partial, data, done + 64);
                        src = sctx->buffer;
                }

                do {
                        sha_transform(sctx->state, src, temp);
                        done += 64;
                        src = data + done;
                } while (done + 63 < len);

                memset(temp, 0, sizeof(temp));
                partial = 0;
        }
        memcpy(sctx->buffer + partial, src, len - done);
}


/* Add padding and return the message digest. */
static void sha1_final(struct crypto_tfm *tfm, u8 *out)
{
        struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
        __be32 *dst = (__be32 *)out;
        u32 i, index, padlen;
        __be64 bits;
        static const u8 padding[64] = { 0x80, };

        bits = cpu_to_be64(sctx->count << 3);

        /* Pad out to 56 mod 64 */
        index = sctx->count & 0x3f;
        padlen = (index < 56) ? (56 - index) : ((64+56) - index);
        sha1_update(tfm, padding, padlen);

        /* Append length */
        sha1_update(tfm, (const u8 *)&bits, sizeof(bits));

        /* Store state in digest */
        for (i = 0; i < 5; i++)
                dst[i] = cpu_to_be32(sctx->state[i]);

        /* Wipe context */
        memset(sctx, 0, sizeof *sctx);
}

static struct crypto_alg alg = {
        .cra_name       =       "sha1",
        .cra_driver_name=       "sha1-generic",
        .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
        .cra_blocksize  =       SHA1_BLOCK_SIZE,
        .cra_ctxsize    =       sizeof(struct sha1_ctx),
        .cra_module     =       THIS_MODULE,
        .cra_alignmask  =       3,
        .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
        .cra_u          =       { .digest = {
        .dia_digestsize =       SHA1_DIGEST_SIZE,
        .dia_init       =       sha1_init,
        .dia_update     =       sha1_update,
        .dia_final      =       sha1_final } }
};

static int __init sha1_generic_mod_init(void)
{
        return crypto_register_alg(&alg);
}

static void __exit sha1_generic_mod_fini(void)
{
        crypto_unregister_alg(&alg);
}

module_init(sha1_generic_mod_init);
module_exit(sha1_generic_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");

MODULE_ALIAS("sha1");